<template>
    <div>
        <router-link
            to="/"
            tag="div"
            class="header-abs"
            v-show="showAbs"
        >
            <div class="iconfont header-abs-back">&#xe624;</div>
        </router-link>
        <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
            景点详情
            <router-link to="/">
                <div class="iconfont header-fixed-back">&#xe624;</div>
            </router-link>
        </div>
    </div>
</template>

<script>
export default {
    name: 'DetailBanner',
    data () {
        return {
            showAbs: true,
            opacityStyle: {
                opacity: 0
            }
        }
    },
    methods: {
        handleScroll () {
            const top = document.documentElement.scrollTop
            if (top > 0) {
                this.showAbs = false
                let opacity = top / 100
                opacity = opacity > 1 ? 1 : opacity
                this.opacityStyle = {opacity}
            } else {
                this.showAbs = true
            }
       }
    },
    mounted () {
        window.addEventListener('scroll', this.handleScroll)
    },
    destroyed () {
        window.removeEventListener('scroll', this.handleScroll)
    }
}
</script>

<style lang="stylus" scoped>
@import '~styles/varibles.styl'

.header-abs
    position: absolute
    height: 50rem
    left: .2rem
    top: .2rem
    width: .8rem
    height: .8rem
    text-align: center
    line-height: .8rem
    border-radius: .4rem
    background-color: rgba(0, 0, 0, .8)
    .header-abs-back
        color: #fff
        font-size: .4rem
  .header-fixed
    position: fixed
    z-index: 2
    top: 0
    left: 0
    right: 0
    overflow: hidden
    height: $headerHeight
    line-height: $headerHeight
    text-align: center
    color: #fff
    background-color: $bgColor
    font-size: .32rem
    .header-fixed-back
      position: absolute
      width: .64rem
      text-align: center
      font-size: .4rem
      top: 0
      left: 0
      color: #fff
</style>
